<!-- Left side column. contains the logo and sidebar -->
<aside class="main-sidebar">
    <!-- sidebar: style can be found in sidebar.less -->
    <section class="sidebar">
        <!-- sidebar menu: : style can be found in sidebar.less -->
        <ul class="sidebar-menu" data-widget="tree">
            <li class="header" style="text-align: center">菜单栏</li>
            {php}echo $tree;{/php}
        </ul>
    </section>
    <!-- /.sidebar -->
</aside>